Cognitive flexibility (i.e. the ability to adapt goal-directed behaviour in response to changed environmental demands) has repeatedly been shown to depend on the prefrontal cortex (PFC). Recent data from primate studies moreover show that depletion of prefrontal 5-HT impairs reversal learning of visual stimuli [Clarke HF, Walker SC, Crofts HS, Dalley JW, Robbins TW, Roberts AC. Prefrontal serot...

La vasectomía constituye un método de anticoncepción electivo para el varón, que consiste en la ligadura o remoción de un segmento de ambos conductos deferentes, evitando así el paso de espermatozoides de los testículos a los conductos eyaculadores. Alrededor de 6% de los pacientes vasectomizados, solicitaran en el futuro la recanalización de la misma. Objetivo: El propósito de este documento e...

We propose a protocol (called RBO) for broadcasting long streams of single-packet messages over radio channel for tiny, battery powered, receivers. The messages are labeled by the keys from some linearly ordered set. The sender repeatedly broadcasts a sequence of many (possibly millions) of messages, while each receiver is interested in reception of a message with a specified key within this se...

An elusive permutation group is a transitive permutation group with no fixed point free elements of prime orders. In this paper we proved that each minimal normal subgroup of an elusive permutation group with squarefree degree is abelian. As an almost immediate consequence, it follows that there are no elusive permutation groups of degree 2pq where p, q are distinct odd primes.

Since the fall of parity in electroweak interactions the discrete transformations of parity, charge conjugation and time reversal are under close scrutiny for any sign of deviation from maximality where symmetry breaking seems to be complete (like P violation in β decay) and for any sign of symmetry breaking when this has not yet been observed (like T violation in

This work presents the results of indoor wideband measurements investigating the spacetime properties of wireless signal transmission with online time reversal precoding. The measurements were conducted using a new time-reversal wideband MIMO channel sounder operating at 2.45 GHz with a bandwidth of 240 MHz. Both line of sight and non line of sight propagation conditions were investigated. Spat...

In this work we derive two families of radix-4 factorizations for the FFT (Fast Fourier Transform) that have the property that both inputs and outputs are addressed in natural order. These factorizations are obtained from another two families of radix-2 algorithms that have the same property. The radix-4 algorithms obtained have the same mathematical complexity (number of multiplications and ad...

Permutation decoding is a technique which involves finding a subset S, called PD-set, of the permutation automorphism group of a code C in order to assist in decoding. A method to obtain s-PD-sets of minimum size s + 1 for partial permutation decoding for binary linear Hadamard codes Hm of length 2 , for all m ≥ 4 and 1 < s ≤ ⌊ 2−m−1 1+m ⌋ , is described. Moreover, a recursive construction to o...

An elusive permutation group is a transitive permutation group with no fixed point free elements of prime order, or equivalently, no nontrivial semiregular subgroups. We provide several new constructions of elusive groups, some of which enable us to build elusive groups with new degrees.

We give a mathematical analysis of the “time-reversal mirror”, in what concerns phenomena described by the genuine acoustic equation with Dirichlet or impedance boundary conditions. An ideal situation is first considered, followed by the boundary-data, impedance and internal time-reversal methods. We explore the relationship between local decay of energy and accuracy of the method, and explain ...